The other day we were in 8man HM TFB, and I used my orb on the TFB before we pulled and he made that sound he makes while you're in combat with him. It didnt pull/start the encounter, just made him make that sound. I've killed that boss dozens of times and I cant recall ever hearing him make that sound while you're waiting to pull. I'll see if I can get it to happen again next week.